In recent years the development of alternative lighting devices to replace traditional incandescent lamps in different lighting applications have resulted in a number of solutions which provide white light by utilizing light emitting diodes, LEDs, in combination with luminescent materials. Luminescent materials, such as phosphors, are materials that emit light (infrared to ultraviolet) under external energy excitation. The incident energy, in the form of high energy electron, photons, or electric field, can then be re-emitted in the form of electromagnetic radiation. Incident energy in the form of radiation within a first range of wavelengths of the electromagnetic spectra is reemitted within a second range of wavelengths of the electromagnetic spectra by the luminescent material. For lighting purposes, at least the second range of wavelengths is selected within the visible range of the electromagnetic spectra. Further, in known lighting devices, to provide a high efficiency of light energy conversion, violet and blue light is utilized to excite the luminescent material. This is shown in U.S. 2009/0176430 A1, which discloses a method of making a white light source by means of arranging a suitable amount of phosphor material on a violet LED, which phosphor material is arranged to emit yellow light subsequently to absorbing violet light. Further, the yellow light is mixed with the violet light, such that a viewer perceives the mixture of blue and yellow light as a white light with a high color rendering index.